Engineering estimates for direct labor hours can be based on engineering drawings analysis and standards for contractors or across the industry.
This tool provides engineering estimates for construction projects based on historical information that relates discrete materials to the amounts of HH used to produce design documents. The remaining elements of the cost (such as quality control or various overheads) can also be taken into account from the direct costs of labor and materials. The different discrete cost estimates are added by simple algebraic equations (hence the common name for "bottoms-up"). The use of engineering estimates requires extensive knowledge of the characteristics of a system (and its components) and a lot of detailed data.